A) NH3
molecular mass of NH3 =(1\(\times atomic \space mass \space of \space N\) ) +\((3\times\) atomic mass of H)
\(=(1\times14 u)+(3\times 1u)\)
=17 u
B) CH3 COOH
molecular mass of CH3 COOH =\((2\times atomic \space mass \space of \space C)\) + (2\(\times atomic \space mass \space of \space O\) ) +(4\(\times atomic \space mass \space of \space H\) )
=\((2\times 12u)+(2\times 16u)+(4\times 1u)\)
=60 u
C) C2H5OH
molecular mass of C2H5OH = \((2\times atomic \space mass \space of \space C)+(6\times atomic \space mass \space of \space H)+(1\times atomic \space mass \space of \space O)\)
=\((2\times 12u)+(6\times 1u)+(1\times 16u)\)
=46 u